EVERETT — A Snohomish County District Court judge who raised public ire for avoiding charges after a drunken-driving arrest last summer has announced plans to retire at the end of the year.

Judge Timothy Ryan sent brief letters notifying the County Council and County Executive Aaron Reardon that he plans to step down Dec. 31.

“It has been an honor and a privilege serving Snohomish County as a District Court Judge,” Ryan wrote in the letter, delivered to county officials Monday.

Ryan, 65, has served on the district court bench in south Snohomish County for two decades.

Before his arrest, Ryan had made it known that he was interested in retiring. Some local attorneys already had started sounding out potential supporters, should they run for the position.

Ryan won re-election to a four-year term in 2010, when he ran unopposed for the nonpartisan seat.

It’s up to the County Council to pick a replacement to serve out the two years remaining on the judge’s term. The council is looking to select an expert panel to help recommend finalists for the job, said Kathryn Bratcher, clerk of the council.

Ryan’s arrest for investigation of drunken driving came on Aug. 29, near his home in the Mill Creek area. Two Washington State Patrol troopers reported that he had bloodshot eyes, slurred speech and smelled of alcohol. They both believed he was driving while impaired.

The arresting trooper, who recognized Ryan, said the judge’s speech sounded “obviously different” from in the courtroom.

Ryan declined to participate in roadside sobriety tests or to undergo a breath test to gauge the level of alcohol in his blood.

The case was transferred to King County to avoid a conflict of interest for local prosecutors and judges.

After reviewing evidence, King County senior deputy prosecutor Erin Norgaard declined to file charges against Ryan, but noted that the judge apparently lied about his alcohol consumption on the night of the arrest.

A major factor in Norgaard’s decision was that Roger Fisher, another district court judge, was expected to testify that Ryan wasn’t impaired. The two friends had been at a restaurant until a few minutes before the traffic stop.

Ryan told the arresting trooper he “had a beer” with Fisher. That conflicted with Fisher’s account that Ryan drank two glasses of wine during a three-hour meal.

Ryan was recovering from hip surgery at the time of the traffic stop, and he likely would be able to offer that explanation for not submitting to roadside sobriety tests, the prosecutor wrote. His refusal to submit to a blood-alcohol test could be offered as consciousness of guilt, but that wouldn’t overcome Fisher’s testimony about Ryan being unaffected by alcohol consumption that evening, Norgaard wrote.

A toxicologist likely would testify that Ryan’s body would have sufficiently metabolized two glasses of wine during a three-hour period to be well below the level of impairment, the prosecutor wrote.

The case provoked outrage among many in the community and inspired debate about how drunken-driving cases are handled after arrest.

Ryan was on sick leave for much of the past few months because of health issues, including problems with his hip following surgery.

He returned to the bench Nov. 13 and has been presiding over hearings, Everett District Court Judge Tam Bui said last week.

He’s expected to remain on the bench, hearing cases until the end of the year.

Ryan faces a mandatory one-year license suspension stemming from his refusal to take a breath test after the stop. It’s set to begin Dec. 27.

The judge canceled a license-suspension hearing scheduled last week with the state Department of Licensing. Instead, Ryan told the state he plans to apply for an ignition interlock device, which would force him to take a breath test before his vehicle could start. That’s a license-restricting option allowed under state law. If he qualifies, he’ll have to pay for the costs related to monitoring his sobriety behind the wheel.

Diana Hefley contributed to this report. Noah Haglund: 425-339-3465, nhaglund@heraldnet.com.